Energy balance is regulated in terms of the economics of both the environment and the internal milieu. The pattern of feeding (what, how much, where, when, how often, how fast, and how long to eat) is determined by the species' niche, the abundance, the availability, and the quality of nutrients in the habitat, the animal's current and future physiological requirements, and competition with other biological important activities. The physiology of the animal is capable of large adjustments to variable environments and the associated variable patterns of food intake. These adjustments, which are often anticipatory, may involve the size of reserves and the amount of energy expenditure and/or conservation. Adjustments may also be behavioral, such as migration, hoarding, shifts in the time and place of feeding, etc. Because of selection pressures, the decisions involved in these adjustments require rules which optimize their consequences. Animals should show "Wisdom of Behavior" as well as "Wisdom of the Body". The wise exploitation of a niche in various habitats requires that the dimensions of the niche be integrated with information about the structure of the current habitat. To investigate the integration of optimality and regulation within niche constraints, we have simulated habitat parameters in a laboratory setting and are examining the precise relationships between costs, benefits, and feeding patterns in several species. Our paradigms allow exploration of how, and in what form, animals acquire estimates of current habitat structure while regulating intake. Animals will be presented with food resources differing in caloric density, nutrient content, temporal patterns of availability and abundance, and time and energy required to find, acquire, and consume. These experiments will be expanded to include environments which vary in the energetic demands placed on the animal and in the availability of alternative, biologically relevant resources. An understanding of the integration of the multiple factors determining behavioral choices may be prerequisite to a complete analysis of feeding and regulation, and their associated disorders, in humans.